Reduce, reuse, recycle
Recycling and reducing waste is core to Shirt-bag, so when cutting up shirts I have kept all the offcuts and unused bits. This resulted in a large pile of shirt cuffs, which inspired the creation of the Off the Cuff tote bag.
Even the handles of the bags are made from the shirt plackets (the bits with the buttons and buttonholes on), using up even more of every shirt.